The present invention relates to a fitting for mounting a cooling apparatus for cooling a micro-processing unit (MPU) used for a personal computer or the like to the MPU, and a removing method of the fitting.
A heating value of an electronic instrument has recently increased in response to high integration of electronic components such as a semiconductor or increase of frequency of an operating clock. A problem of how junction temperatures of respective electronic components are kept within an operating temperature range becomes serious for normally operating the electronic components.
Especially, the integration and frequency of the MPU are extremely increased, so that measures against heat radiation become important for stabilizing an operation and securing the operating life.
The heat of the MPU mounted to an MPU socket is radiated by a heat sink and a fan having a motor. The heat sink increases a large heat radiating area and exchanges the heat with a refrigerant such as air. The fan forcibly feeds the refrigerant such as the air to the heat sink. Generally, the heat sink is removably mounted to the MPU so that the MPU can be replaced with a new MPU when the MPU fails or needs to be replaced.
Examples of a mounting structure and a mounting method of a conventional heat sink to an MPU are described with reference to FIG. 7 through FIG. 10.
FIG. 7 is a perspective view of an entire MPUxe2x80x94heat sinkxe2x80x94fan assembly using a mounting fitting of the conventional heat sink, and FIG. 8 is a perspective view of the mounting fitting of the conventional heat sink. FIG. 9A, FIG. 9B, and FIG. 9C are sectional views of the heat sink and the fitting, and are used for illustrating a mounting method of the mounting fitting of the conventional heat sink. FIG. 10A, FIG. 10B, and FIG. 10C are sectional views of the heat sink and the fitting, and are used for illustrating a removing method of the mounting fitting of the conventional heat sink.
In FIG. 7 and FIG. 9A, MPU socket 1 is entirely formed in a plate shape having a predetermined thickness, and has first locking claw 1a and second locking claw 1b on its one side and the other side, respectively. MPU 2 of a pin grid array (PGA) type package generating heat is mounted on MPU socket 1, and heat sink 13 touches on the upper surface of MPU 2 and radiates heat from MPU 2.
Heat sink 13 has base part 13a in its lower part and fin part 13b disposed on base part 13a. Fin part 13b receives the heat conducted from base part 13a and radiates the heat to ambient air.
Fan 4 is disposed on heat sink 13 and forcibly air-cools the heat sink 13. Mounting fitting 15 is disposed on heat sink 13 and fixes heat sink 13.
Mounting fitting 15 is entirely formed in an M shape. Mounting fitting 15 comprises the following elements:
(a) first spring 15a and second spring 15b disposed in the intermediate positions;
(b) fulcrum 15c that is disposed in the boundary between first spring 15a and second spring 15b and presses heat sink 13;
(c) first arm 15d connecting to an end of first spring 15a on the opposite side to fulcrum 15c; 
(d) second arm 15e connecting to an end of second spring 15b on the opposite side to fulcrum 15c; 
(e) plate part 15f disposed on first arm 15d and having a first locking hole engaging with first locking claw 1a; 
(f) plate part 15g disposed on second arm 15e and having a second locking hole engaging with second locking claw 1b; 
(g) plate part 15h having a square hole and formed near the directly above part of plate part 15g having the second locking hole. Bar 6 is a precision screwdriver for removal, and is thin and highly rigid.
A cooling operation of a cooling apparatus comprising the components discussed above is briefly described. The heat generated from MPU 2 is received by the bottom surface of base part 13a, and diffuses inside base part 13a. The heat then conducts to fin part 13b functioning as a heat radiating fin, is forcibly air-cooled by fan 4, and is radiated to the ambient air.
Referring to FIG. 9A, FIG. 9B, and FIG. 9C, there is described a method of crimping and fixing heat sink 13 onto MPU 2.
Firstly, heat sink 13 is placed on MPU 2 mounted to MPU socket 1, mounting fitting 15 is placed on heat sink 13, and plate part 15f having the first locking hole is hooked on first locking claw 1a of socket 1 (FIG. 9A).
Then, while fulcrum 15c of mounting fitting 15 is in contact with the upper face of base part 13a of heat sink 13, a load (P1 shown in FIG. 9B) is applied to second spring 15b to press it down until the tip of second arm 15e contacts with the upper part of second locking claw 1b of socket 1 (FIG. 9B). When second spring 15b is further pressed down, the lower part of second arm 15e touches on the slope (S shown in FIG. 9B) of the upper part of second locking claw 1b to open second arm 15e. Therefore, plate part 15g having the second locking hole is finally hooked on second locking claw 1b (FIG. 9C). Fan 4 may be mounted on heat sink 13 after that, or may be previously mounted on heat sink 13.
Referring to FIG. 10A, FIG. 10B, and FIG. 10C, there is described a method of removing heat sink 13. Firstly, bar 6 is inserted into the square hole in plate part 15h of mounting fitting 15, and a load (P2 shown in FIG. 10A) is applied to bar 6 to press bar 6 down until the lower end of plate part 15g having the second locking hole moves below the lower end of second locking claw 1b of socket 1 (FIG. 10A).
Then, a load (M2 shown in FIG. 10B) is applied to bar 6 with load P2 applied, thereby bending second arm 15e of mounting fitting 15 outwardly (FIG. 10B). When load P2 for pressing down second arm 15e is then removed, plate part 15g having the second locking hole comes off second locking claw 1b due to restoring forces of first spring 15a and second spring 15b of mounting fitting 15 (FIG. 10C). When plate part 15f having the first locking hole hooked on first locking claw 1a is removed, the entire mounting fitting 15 is removed to allow heat sink 13 to be removed.
In another embodiment, mounting fitting 15 may be a link mechanism assembly comprising a plurality of components as shown by a perspective view of a mounting fitting of another conventional heat sink of FIG. 11. FIG. 12 is a perspective view of an entire MPUxe2x80x94heat sinkxe2x80x94fan assembly using the mounting fitting of the heat sink of FIG. 11.
A substantially M-shaped mounting fitting made of a plate-like elastic material crimps and fixes a heat sink onto a heating element. The heating element is mounted on a socket, and the heat sink diffuses heat from the heating element. The mounting fitting of the heat sink comprises the following elements: a first spring; a second spring coupled to the first spring; a central part that is a boundary part between the first spring and the second spring and functions as a fulcrum for pressing the heat sink; a first arm connected to an end of the first spring on the opposite side from the fulcrum; a second arm connected to an end of the second spring on the opposite side from the fulcrum; a plate part having a small hole and formed in the second spring and near the second arm; and a stopper formed in a space sandwiched between the second spring and the second arm.